How-to Make Side Cupboard Extension to Built-in Corner Unit
In conjunction with a recent makeover of our kitchen my wife and I decided we would also do a makeover of our dining room; as part of this planned makeover my wife asked if I could make more cupboard space.
After putting some thought into it (over a cup of coffee) the obvious choice that came to me was to build a side cupboard extension to the existing built-in corner unit.
Having discussed my ideas with my wife the objectives I set myself for this project were:-
- The cupboard extension should match the existing corner unit in design and finish.
- It should look aesthetically pleasing and proportionate to the space e.g. not overbearing.
- Be of quality build, and durable, and
- Be made using recycled wood to minimize on costs.
Background: Previous Cupboard Extensions
When we bought the house the corner unit in the dining room was already there, but at that time it only consisted of the base cupboard and the shelving unit on top.
During the first couple of years we did what most couples do and did a makeover of each room in turn. On doing the makeover of the toilet and shower room I removed the existing louvre door and replaced it with a concertina door. Then when doing the makeover of the dining room I added a new cupboard on top of the shelving of the corner unit; matching it to the existing unit in design and finish. The new cupboard was made from recycled wood, and to match the door of this with the base cupboard I used wood from the old louvre door which I'd previously removed from the toilet room.
Then, many years later, while redecorating the dining room again, I took the opportunity to make a built-in Welsh Dresser (including drawers) on top of the existing built-in cupboard in the alcove on the opposite side of the room to the corner unit. Again, I used recycled wood (and glass), and matched the general appearance of the new with the existing. The glass I used for the Welsh Dresser doors being recycled from our old porch, which I’d previously renovated when I replaced all the rotting window frames (small Edwardian style windows) with large windows; making the porch a more contemporary design.
When we bought our house the doors on our toilet shower room were louvre doors. As nice as they were, when opened, the doors took up too much valuable space for such a small room as the toilet.
Therefore (as explained above) I’d taken the doors out and replaced them with a concertina door, which takes up the minimal of space. Then, over the years, I’d used one of the louvre doors in various DIY projects including the cupboard extension above the corner unit, and for a small cupboard in our front porch.
While the other louvre door, which I stored in the back of my workshop, would now be down-sized to make two new louvre doors for the new cupboard side extension.
Space Saving Ideas
When doing a makeover of a room do you look for ways to maximise use of space?
As the new built-in cupboard would be built onto the side of the existing corner unit, it wasn’t a case of building and assembly it in my workshop; as I would normally do. It was a matter of building it in stages (in situ) to fit against the wall and onto the side of the existing corner unit.
To achieve this, the main stages of construction would be:-
- To make the carcase; top and side.
- Add a door post, skirting board and decorative mouldings to the carcass.
- Make and fit new louvre doors from the old toilet room door.
- Wood stain the new side cupboard to match the existing corner unit, and
- Fit the door knobs to the new doors to match with the knobs on the existing cupboard doors.
For the top I had a spare piece of half inch (12mm) structural plywood in my workshop that was just about the right size, and which would be ideal. The only real issue (which may not be obvious from the photos) is that the sides of the existing base unit slopes from the door to the wall at an angle (about 15 degrees). So I couldn’t make the top by just measuring twice and cutting once; I also needed to ensure I cut one end of the top piece at the correct angle.
Therefore, after trimming the top to the correct width; to mark the cut line for its length, I placed the panel to overlap the surface of the existing cupboard, and then scored a pencil line from underneath.
As I was butt joining the two surfaces, and with it being the top (visible) surface, the join would have to be near perfect. So after cutting the correct angle with the circular saw, I test fitted the new piece in place and remarked for a perfect fit e.g. just a couple more millimetres needed to be trimmed off one end than the other.
To get the precision trim, I wanted the panel clamped on end so that I had full control over trimming it with my electric planer. I could quite easily have used the wood vice in my workshop, but as it was such a nice sunny day I decided to rig up a makeshift vice outside; by using the patio table as a workbench (as I often do on nice days), as shown in the photo below.
Once the top was cut to size and sanded smooth I then screwed two support beams to the underside; one in the front and the other at the back; their purpose being:-
- To add strength to the top, to ensure it stayed rigid when in use.
- A means of securing the cupboard extension in place by screwing through the back support beam into the wall, and
- The front beam acting as the top doorframe for the cupboard doors, and also serving as a backing for mounting decorative moulding to blend in with the moulding on the existing cupboard.
For making the side panel, I didn’t have any suitable plywood offcuts left; but I did find a side panel from an old cupboard, which I'd been given by a friend for recycling. It was a good piece of plywood with a nice veneer finish; typical of 1950s style furniture.
However, once I’d cut it to size it became obvious that the veneer was flaking off. So rather than try to restore the veneer I decided to shave the loose veneer off with a chisel and then smooth the surface back to the bare wood with a belt sander.
Once the side panel was cut to size and sanded, to fit it snugly against the back wall I needed to cut the profile of the skirting board; which I did by using a profile gauge and jig saw.
The simplest method to secure the top in place, and to provide support for it, was to fix a support batten against the existing cupboard. The only difficulty in doing this was shape of the decorative moulding preventing a flat piece of wood being screwed directly against the side of the cupboard.
The two obvious options to me were either to:-
- Remove the decorative moulding from the side of the cupboard; in order to give a flat surface that a support batten could be screwed directly to, or
- Find or make an ‘L’ shaped batten that would fit around the moulding.
As it happened, the excess wood I cut from the side panel was ‘L’ shaped, and it looked to be about the right dimension. So on doing a test fit I confirmed that apart from being 6mm (quarter of an inch) short in height, it was near perfect fit.
Therefore, after finding a spare piece of 6mm wood beading in my workshop, I cut the ‘L’ shaped off-cut to the correct length and glued the 6mm wood beading to the top of it. I then fitted it in place over the moulding on the side of the existing base cupboard.
With the support batten in place, it was simply a case of assembling the top and the side panel in situ. The top panel could then be supported by the batten on one side and by the side panel at the other end; and then secured in place with glue and screws.
I then levelled the new and existing cupboard tops with each other by running my belt sander across the join between the two surfaces.
One of the louvre doors would be hinged directly to the side panel, but there was nowhere to hang the other door; therefore I needed a doorpost from which I could hang the other door. Because the cupboard side was angled, and not square, I couldn’t simply screw a piece of timber to it to act as a doorpost. I needed to make the doorpost with one surface being the same angle as the cupboard side.
Therefore, after finding a suitable piece of 1x2 inch planed timber in my workshop, I used my electric planer to chamfer the wide edge of the timber to the same angle as the cupboard side; and then glued and screwed it into place.
Downsizing the Old Louvre Door
To make the new louvre doors for the cupboard extension I needed to downsize the old door. Something I’d done on a number of occasions on other projects in the past; so it was becoming second nature.
Optionally, I could go as far as making proper mortise and tenon joints for the frame, but I’ve previously discovered that once the slats are re-glued a simple butt joint is more sufficient to make the door solid.
As the original door was 2 metres high (6 feet and 6 inches), and the new doors would be 2 feet high, I had plenty of wood to play with.
Step by step guide for downsizing the old louvre door to make two new ones:-
- Cut the old door to the correct height for the new doors.
- Calculate the width to cut. The width of the new door less, the width of the side frame minus the depth the slats that go into the side frame. As an example, if the overall door width was to be 300mm and the side frame was 40mm, but the slats fit into the side frame by 5mm, then the width to cut would be 300-40+5 = 265mm.
- Cut the door to the calculated width.
- If the cut section includes a top or bottom frame, then cut that down to size by the amount the slats fit into the side frame e.g. reduce it by a further 5mm.
- Put the good section to one side e.g. the section cut to the correct width. Then knock the slats out from the other side frame. The surplus slats usually come out quite easily, but sometimes may need a little gentle persuasion with a wooden mallet; making sure not to hit them so hard as to split the wood in the side frame.
- Gently clean out any old glue, or bits of wood, from the slat holes with a small chisel and mallet.
- Put a dab of glue in each slat hole in the side frame.
- Put the good section in a wood vice and place the side frame on top, lining up the slat holes with the slats.
- Gently tap in place with a wooden mallet.
- Then clamp together until the glue has set.
- In the meantime, measure and cut the top and or bottom sections of the door; and using offcuts from the old louvre door, cut sections of wood to fit snuggly.
- Secure the new top/bottom frame sections, either with half or butt joints, and screw and glue in place.
Decorative Mouldings and Skirting
While waiting for the glue to dry on the newly made louvre doors, I paid attention to the decorative mouldings above the doors, and to fitting the skirting around the base of the cupboard before fitting the doors.
Ideally I would like to have found an exact match for the existing decorative mouldings. I checked the mouldings in my workshop and online for a match with the existing but couldn’t find anything. However, in my workshop I did find some spare decorative moulding that was a close match, and which was the same overall dimensions. So before fitting the doors I cut a piece to size and glued and tacked it into position with invisible wire nails from my nail gun. An invisible nail is a millimetre thick wire nail that penetrates the wood, making such a small hole that once the surface is wood stained the nail becomes invisible.
To fit the skirting Board across the front base of the cupboard I first fitted a solid piece of salvaged timber (from my workshop) to the same height as the skirting; so the skirting board could then be firmly tacked to it and glued in place.
Fitting the Doors
Allowing a few millimetres (eighth of an inch clearance all round) the doors were first test fitted; and any minor adjustments were then made with my electric planner. Once I was satisfied with the fit I hinged and fitted the doors; and then fitted the door knobs to match the existing cupboards.
It’s always best to aim for a tight fit with a door because:-
- If the fit is a bit too tight you can always trim to get a perfect fit with an electric planner, but it’s not always so easy to put right if you make it too small. Albeit, if the door is too small you can often add a trim to make it bigger; so that it’s a better fit.
- Where wood has been in storage in a shed or workshop for a while it’s likely to have swollen due to the higher humidity; and then shrink back when used in the house because of the dryer atmosphere of modern central heated homes. If you plan ahead, you can compensate for this to a large extent by storing the wood you intend using into the house a few weeks in advance; to let it acclimatise to its new environment.
To make the shelving I still had some MDF in my workshop, which I friend gave me. I’d previously used some of it on another project, but I had just enough left over to make a couple of shelves for the cupboard. It’s not a material I normally use as I prefer the look and feel of natural wood, but for shelving its ideal; especially as it was free anyway.
I measured and cut the MDF to size to make two shelves, and then fitted them in place using corner brackets on one side and screwing into them through the side panel on the other side.
For the base of the cupboard, rather than making a false bottom, as I might normally do, I decided to keep it open to maximise on usable space e.g. to give extra height for storage in the bottom of the cupboard.
Wood Staining and Completion
To blend the surfaces of the new cupboard with the existing I applied three coats of Ronseal Rosewood wood stain; allowing four hours to dry between each coat. Then before applying the last coat I lightly sanded the surfaces to give a smooth finish.
I have used other branded wood stains in the past, including Sikkens and sadolin, which I find are just as good; but their drying times tends to be far too long e.g. 16 hours to 24 hours, and even then they can take far longer to dry than stated on the tin. Whereas, the Ronseal wood stain dries within four hours (according to the tin), although in practice it often dries in half that time.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2017 Arthur Russ